1.\" $OpenBSD: grep.1,v 1.40 2011/03/04 03:11:22 tedu Exp $ 2.\" Copyright (c) 1980, 1990, 1993 3.\" The Regents of the University of California. All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. Neither the name of the University nor the names of its contributors 14.\" may be used to endorse or promote products derived from this software 15.\" without specific prior written permission. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27.\" SUCH DAMAGE. 28.\" 29.\" @(#)grep.1 8.3 (Berkeley) 4/18/94 30.\" 31.Dd $Mdocdate: March 4 2011 $ 32.Dt GREP 1 33.Os 34.Sh NAME 35.Nm grep , egrep , fgrep , 36.Nm zgrep , zegrep , zfgrep 37.Nd file pattern searcher 38.Sh SYNOPSIS 39.Nm grep 40.Bk -words 41.Op Fl abcEFGHhIiLlnqRsUVvwxZ 42.Op Fl A Ar num 43.Op Fl B Ar num 44.Op Fl C Ns Op Ar num 45.Op Fl e Ar pattern 46.Op Fl f Ar file 47.Op Fl -binary-files Ns = Ns Ar value 48.Op Fl -context Ns Op = Ns Ar num 49.Op Fl -line-buffered 50.Op Ar pattern 51.Op Ar 52.Ek 53.Sh DESCRIPTION 54The 55.Nm grep 56utility searches any given input files, 57selecting lines that match one or more patterns. 58By default, a pattern matches an input line if the regular expression 59(RE) in the pattern matches the input line 60without its trailing newline. 61An empty expression matches every line. 62Each input line that matches at least one of the patterns is written 63to the standard output. 64If no file arguments are specified, the standard input is used. 65.Pp 66.Nm grep 67is used for simple patterns and 68basic regular expressions 69.Pq BREs ; 70.Nm egrep 71can handle extended regular expressions 72.Pq EREs . 73See 74.Xr re_format 7 75for more information on regular expressions. 76.Nm fgrep 77is quicker than both 78.Nm grep 79and 80.Nm egrep , 81but can only handle fixed patterns 82(i.e. it does not interpret regular expressions). 83Patterns may consist of one or more lines, 84allowing any of the pattern lines to match a portion of the input. 85.Pp 86.Nm zgrep , 87.Nm zegrep , 88and 89.Nm zfgrep 90act like 91.Nm grep , 92.Nm egrep , 93and 94.Nm fgrep , 95respectively, but accept input files compressed with the 96.Xr compress 1 97or 98.Xr gzip 1 99compression utilities. 100.Pp 101The following options are available: 102.Bl -tag -width indent 103.It Fl A Ar num 104Print 105.Ar num 106lines of trailing context after each match. 107See also the 108.Fl B 109and 110.Fl C 111options. 112.It Fl a 113Treat all files as ASCII text. 114Normally 115.Nm 116will simply print 117.Dq Binary file ... matches 118if files contain binary characters. 119Use of this option forces 120.Nm 121to output lines matching the specified pattern. 122.It Fl B Ar num 123Print 124.Ar num 125lines of leading context before each match. 126See also the 127.Fl A 128and 129.Fl C 130options. 131.It Fl b 132The offset in bytes of a matched pattern is 133displayed in front of the respective matched line. 134.It Fl C Ns Op Ar num 135Print 136.Ar num 137lines of leading and trailing context surrounding each match. 138The default is 2 and is equivalent to 139.Fl A 140.Ar 2 141.Fl B 142.Ar 2 . 143Note: 144no whitespace may be given between the option and its argument. 145.It Fl c 146Only a count of selected lines is written to standard output. 147.It Fl E 148Interpret 149.Ar pattern 150as an extended regular expression 151(i.e. force 152.Nm grep 153to behave as 154.Nm egrep ) . 155.It Fl e Ar pattern 156Specify a pattern used during the search of the input: 157an input line is selected if it matches any of the specified patterns. 158This option is most useful when multiple 159.Fl e 160options are used to specify multiple patterns, 161or when a pattern begins with a dash 162.Pq Sq - . 163.It Fl F 164Interpret 165.Ar pattern 166as a set of fixed strings 167(i.e. force 168.Nm grep 169to behave as 170.Nm fgrep ) . 171.It Fl f Ar file 172Read one or more newline separated patterns from 173.Ar file . 174Empty pattern lines match every input line. 175Newlines are not considered part of a pattern. 176If 177.Ar file 178is empty, nothing is matched. 179.It Fl G 180Interpret 181.Ar pattern 182as a basic regular expression 183(i.e. force 184.Nm grep 185to behave as traditional 186.Nm grep ) . 187.It Fl H 188Always print filename headers 189.Pq i.e. filenames 190with output lines. 191.It Fl h 192Never print filename headers 193.Pq i.e. filenames 194with output lines. 195.It Fl I 196Ignore binary files. 197.It Fl i 198Perform case insensitive matching. 199By default, 200.Nm grep 201is case sensitive. 202.It Fl L 203Only the names of files not containing selected lines are written to 204standard output. 205Pathnames are listed once per file searched. 206If the standard input is searched, the string 207.Dq (standard input) 208is written. 209.It Fl l 210Only the names of files containing selected lines are written to 211standard output. 212.Nm grep 213will only search a file until a match has been found, 214making searches potentially less expensive. 215Pathnames are listed once per file searched. 216If the standard input is searched, the string 217.Dq (standard input) 218is written. 219.It Fl n 220Each output line is preceded by its relative line number in the file, 221starting at line 1. 222The line number counter is reset for each file processed. 223This option is ignored if 224.Fl c , 225.Fl L , 226.Fl l , 227or 228.Fl q 229is 230specified. 231.It Fl q 232Quiet mode: 233suppress normal output. 234.Nm grep 235will only search a file until a match has been found, 236making searches potentially less expensive. 237.It Fl R 238Recursively search subdirectories listed. 239.It Fl s 240Silent mode. 241Nonexistent and unreadable files are ignored 242(i.e. their error messages are suppressed). 243.It Fl U 244Search binary files, but do not attempt to print them. 245.It Fl V 246Display version information. 247All other options are ignored. 248.It Fl v 249Selected lines are those 250.Em not 251matching any of the specified patterns. 252.It Fl w 253The expression is searched for as a word (as if surrounded by 254.Sq [[:<:]] 255and 256.Sq [[:>:]] ; 257see 258.Xr re_format 7 ) . 259.It Fl x 260Only input lines selected against an entire fixed string or regular 261expression are considered to be matching lines. 262.It Fl Z 263Force 264.Nm grep 265to behave as 266.Nm zgrep . 267.It Fl Fl binary-files Ns = Ns Ar value 268Controls searching and printing of binary files. 269Options are 270.Ar binary , 271the default: search binary files but do not print them; 272.Ar without-match : 273do not search binary files; 274and 275.Ar text : 276treat all files as text. 277.Sm off 278.It Fl Fl context Op = Ar num 279.Sm on 280Print 281.Ar num 282lines of leading and trailing context. 283The default is 2. 284.It Fl Fl line-buffered 285Force output to be line buffered. 286By default, output is line buffered when standard output is a terminal 287and block buffered otherwise. 288.Pp 289.El 290.Sh EXIT STATUS 291The 292.Nm grep 293utility exits with one of the following values: 294.Pp 295.Bl -tag -width Ds -offset indent -compact 296.It Li 0 297One or more lines were selected. 298.It Li 1 299No lines were selected. 300.It Li \*(Gt1 301An error occurred. 302.El 303.Sh EXAMPLES 304To find all occurrences of the word 305.Sq patricia 306in a file: 307.Pp 308.Dl $ grep 'patricia' myfile 309.Pp 310To find all occurrences of the pattern 311.Ql .Pp 312at the beginning of a line: 313.Pp 314.Dl $ grep '^\e.Pp' myfile 315.Pp 316The apostrophes ensure the entire expression is evaluated by 317.Nm grep 318instead of by the user's shell. 319The caret 320.Ql ^ 321matches the null string at the beginning of a line, 322and the 323.Ql \e 324escapes the 325.Ql \&. , 326which would otherwise match any character. 327.Pp 328To find all lines in a file which do not contain the words 329.Sq foo 330or 331.Sq bar : 332.Pp 333.Dl $ grep -v -e 'foo' -e 'bar' myfile 334.Pp 335A simple example of an extended regular expression: 336.Pp 337.Dl $ egrep '19|20|25' calendar 338.Pp 339Peruses the file 340.Sq calendar 341looking for either 19, 20, or 25. 342.Sh SEE ALSO 343.Xr ed 1 , 344.Xr ex 1 , 345.Xr gzip 1 , 346.Xr sed 1 , 347.Xr re_format 7 348.Sh STANDARDS 349The 350.Nm 351utility is compliant with the 352.St -p1003.1-2008 353specification. 354.Pp 355The flags 356.Op Fl AaBbCGHhILRUVwZ 357are extensions to that specification, and the behaviour of the 358.Fl f 359flag when used with an empty pattern file is left undefined. 360.Pp 361All long options are provided for compatibility with 362GNU versions of this utility. 363.Pp 364Historic versions of the 365.Nm grep 366utility also supported the flags 367.Op Fl ruy . 368This implementation supports those options; 369however, their use is strongly discouraged. 370.Sh HISTORY 371The 372.Nm grep 373command first appeared in 374.At v6 . 375